1. Field of the Invention
The present invention relates generally to bumpers for motor vehicles and, more specifically, to a bumper system for a motor vehicle.
2. Description of the Related Art
It is known to provide a bumper system for a front end or rear end of a motor vehicle. For a front end of the motor vehicle, the bumper system typically includes a bumper beam extending transversely and secured to a forward end of a pair of front rails, which extend longitudinally and are spaced transversely. The bumper system also includes an energy absorber extending transversely and secured to the bumper beam. The bumper system may include a fascia disposed over and covering the energy absorber.
It is also known that the bumper system protects a body of the motor vehicle from low speed impact with an object through elastic or semi-plastic deformation of the energy absorber. It is further known that the bumper system is an absorber for high-speed impact with an object through major plastic deformation of the bumper beam. It is yet further known that bumper beams of bumper systems tend to buckle at a centerline in an uncontrolled fashion during low and highspeed impacts.
Although the above bumper system has worked, it suffers from the disadvantage that the bumper beam has a constant cross-section which is either too weak to resist low speed impact at a center thereof or makes it too strong to absorb impact energy before the supporting vehicle rails collapse under the motor vehicle. As a result, it is desirable to provide a bumper system having a bumper beam which will better balance both low speed impact protection and high speed energy absorption for a bumper system of a motor vehicle. It is also desirable to provide a reinforcement for a bumper beam that reduces damage to the bumper beam at low speed impacts but allows the bumper beam to crush at high-speed impacts. It is further desirable to provide a metal device positioned behind or inside a bumper beam that when impacted crushes with an efficient and effective energy curve. Therefore, there is a need in the art to provide a bumper system that meets these desires.
Accordingly, the present invention is a bumper system for a motor vehicle. The bumper system includes an energy absorber and a bumper beam connected to the energy absorber and for connection to vehicle structure and having a general B shape. The bumper system also includes a member disposed between the bumper beam and a rail of the motor vehicle to absorb energy during an impact with an object by the bumper system.
One advantage of the present invention is that a new bumper system is provided for a motor vehicle. Another advantage of the present invention is that the bumper system includes a bumper beam made from a manufacturing process such as a roll formed process or an extrusion process with a generally xe2x80x9cBxe2x80x9d shaped cross-section which balances both low-speed impact and high-speed impact of the motor vehicle. Yet another advantage of the present invention is that the bumper system has a reinforcement attached to a xe2x80x9cBxe2x80x9d shaped bumper beam that reduces damage to the bumper beam at a low speed impact but allows the bumper beam to crush at a high-speed impact. Still another advantage of the present invention is that the bumper system includes a centerline bumper reinforcement of unique cross-sectional geometry, allowing the bumper beam to crush at high speed yet resist low speed damage. A further advantage of the present invention is that the bumper beam reinforcement resists excessive centerline bending deformation. Yet a further advantage of the present invention is that the bumper system includes a metal device is positioned behind or inside a vehicle bumper beam that when impacted crushes with an efficient and effective energy curve. Still a further advantage of the present invention is that the metal device is relatively low cost to manufacture compared to more expensive hydraulic strut assemblies. Another advantage of the present invention is that the metal device has a unique geometry and simplicity and crushes in a very efficient manner. Yet another advantage of the present invention is that the metal device reduces cost during repair of a vehicle after an incidental collision. Still another advantage of the present invention is that the metal device is low cost to manufacture, lighter than traditional strut designs, low cost to assembly and service in the field, very efficient crush characteristics (square load-deflection curve), ease of design flexibility for different vehicles, ease of design to commonize part between vehicles, greatly reduces the cost to repair, and offers a controlled joint to bumper beam which allows for improved high speed energy management with lower intrusion into an occupant compartment of the vehicle.
Other features and advantages of the present invention will be readily appreciated, as the same becomes better understood, after reading the subsequent description when considered in connection with the accompanying drawings.